I got the following as a PM a couple days ago... I felt it was a question that belonged in the forums, so I've copied the original message and my response over to here... If anyone else has advice for Frank S. I'm sure he'd welcome it.
This is the kind of question that is more appropriate for the forums, where you can get more than just one opinion... I'm taking the liberty of copying this message to the Boiler Room area, as it seems more fitting there.
First off, I advise EXTREME caution, as a badly designed / operated water heating system can explode with devastating results! At the very least, ensure that the system has a temperature / pressure relief valve on it, and that there is no way to shut the water flow off so that the stove is isolated in a closed section of piping.
I'm also not sure how good an idea this is, or how effective it would be. Your stove is (hopefully) designed to radiate almost all the heat that it produces into the room, with just enough left to make the draft work so as to get proper combustion. Putting a heat exchanger in or on the pipe will cool the smoke, possibly getting rid of your draft, and probably contributing to extra creosote buildup. Putting the exchanger on the outside of the stove potentially could cause the firebox to cool enough that you lose the secondary combustion, again giving more creosote, and lower burning efficiency.... I don't know if you can pull enough heat out of the system to be worth the trouble and without causing negative side effects.
I would advise against putting anything inside the flue pipe, as that will increase the difficulty of cleaning the system. There are also potential issues of acids in the exhaust attacking the heater materials.
What I've seen that looked most effective for a stove pipe setup was a water jacket around one section of pipe - sort of like a double wall pipe with the water in the space between. That way the smoke wasn't obstructed and you had maximal heat exchange surface. Another approach I've seen is to make a serpentine pattern of copper tubing attached to the outside of the stove. Make sure to have some way of regulating the flow through the exchanger so you can control how much heat you pull out.
Gooserider
This is the kind of question that is more appropriate for the forums, where you can get more than just one opinion... I'm taking the liberty of copying this message to the Boiler Room area, as it seems more fitting there.
First off, I advise EXTREME caution, as a badly designed / operated water heating system can explode with devastating results! At the very least, ensure that the system has a temperature / pressure relief valve on it, and that there is no way to shut the water flow off so that the stove is isolated in a closed section of piping.
I'm also not sure how good an idea this is, or how effective it would be. Your stove is (hopefully) designed to radiate almost all the heat that it produces into the room, with just enough left to make the draft work so as to get proper combustion. Putting a heat exchanger in or on the pipe will cool the smoke, possibly getting rid of your draft, and probably contributing to extra creosote buildup. Putting the exchanger on the outside of the stove potentially could cause the firebox to cool enough that you lose the secondary combustion, again giving more creosote, and lower burning efficiency.... I don't know if you can pull enough heat out of the system to be worth the trouble and without causing negative side effects.
I would advise against putting anything inside the flue pipe, as that will increase the difficulty of cleaning the system. There are also potential issues of acids in the exhaust attacking the heater materials.
What I've seen that looked most effective for a stove pipe setup was a water jacket around one section of pipe - sort of like a double wall pipe with the water in the space between. That way the smoke wasn't obstructed and you had maximal heat exchange surface. Another approach I've seen is to make a serpentine pattern of copper tubing attached to the outside of the stove. Make sure to have some way of regulating the flow through the exchanger so you can control how much heat you pull out.
Gooserider
Not to hijack the thread, but how goes the battle for you?
